Real world and crazy ideas on next generation PHP programming approaches

1. Magento
AOP, Metaprogramming, Codeg
eneration
Or the way of throwing elephants to a blackbox.
Serge Smertin

2. Magento
About
 Zend Certified Engineer
 Senior Sw. Engineer @ EPAM
 PHP since 2005
 CakePHP since 2007
 Zend Framework since 2008
 Yii since 2010
 Symfony 2.0 since 2011
 Can also tell you something
about pros & cons of
CodeIgniner, Drupal, Wordpress

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Agenda
Inversion of control
Metaprogramming
Unexpected & Interesting
Codegeneration
Real life usage

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Design matters: SOLID
5 principles of enterprise object-oriented
design:
• Single responsibility
• Open-close
• Liskov substitution
• Interface segregation
• Dependency injection

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Dependency Injection
Only possible with some kind of service locator
Makes able to lazy initialize all resource
dependencies
Simplify debugging and development
Simplify existing components extension and
integration
Dependency injection in PHP 5.3/5.4
http://slidesha.re/vE8Wyp

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Service locators in PHP
Most of them require build stage
For performance reasons they
leverage codegeneration
Require dependency configuration in
some of the established ways
Heavily utilize Reflection API

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Why building?

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Pimple
 73 lines of PHP code
 Use closures heavily
 Made as fun proof of concept
 Good for little projects
 Base of Silex microframework
 URLS
• Pimple: http://pimple.sensiolabs.org/
• Silex project: http://silex.sensiolabs.org/

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Symfony 2 DI Component
 Mature production ready
 Stores configuration within XML, YAML or annotations
 Support for event observers
 Support for custom service tagging
 Scopes
 Require build step for deploy
 Supported by Sensio Labs. Paid subscriptions available
 Could be integrated through PEAR
 Easy 
 URLS go here:
• DI for PHP 5.2 - http://bit.ly/uGt8CK
• PEAR channel: http://pear.symfony.com/
• Service Container - http://bit.ly/s7F8HF

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Some cookies: CLI
 Some tasks could be
done through CLI easier
 Cron?
 Daemons?
 Continuous integration?
 Expose services to
console?

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cli:call
 What about writing
custom command for
accessing nearly
every defined service
in container for
isolated working?
$ ./app/console cli:call
service.name methodName
[arg1, arg2, arg3, …]

12. Magento
Metaprogramming
Is how programs are self-aware
Is not recommended to use at run time
Is the art of operating metadata
Is black magic processed at build step
Is possible with PHP 5
Is making the code shorter

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Metadata
XML files
YAML files
Database
Naming conventions

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Metadata
XML files
YAML files
Database
Naming conventions
… boring.

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Metadata
XML files PHP doc comments
YAML files PHP code itself
Database Reflection
Naming Annotations
conventions SQL code

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Reflection API
 A way of retrieving information about
parameters for a class method
 A way of accessing private property of a
parent class
 A way of passing method parameters by name
 Another way of making callback
 Other more or less interesting ways of
application

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Annotation magic
 Actually are custom docblock tags with some extend
 Some kind of XDoclet API for PHP
 Some other couple of words here
 Some frameworks endorse usage: Symfony2 & FLOW3
 Couple of existing solutions available
• Regular expressions 
• PHPUnit
• ZendReflectionDocblockTag (just extended PCRE, actually)
• Doctrine annotation reader (parser-based method)
 Links:
• Doctrine Annotations Reference http://bit.ly/s6kQfh
• An article of 2008 http://bit.ly/uT1v2U
• XDoclet overview of 2005 http://bit.ly/tYy8pa

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Tokenization
 Just token_get_all() and
be insane
 Build a classmap file with
namespace information
 Generate unit test
skeletons
 Put all TODO’s in
comments as tickets to
Jira
 Some of more
sophisticated things I
haven’t thought about

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SQL code: annotations. Why not?

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SQL: Sharding. Annotations?..
 Get meta-info about sharded connection to
use from query directly
 Or parse the query, but little longer
 /*entity customer://1234 */
SELECT name FROM customer WHERE
id = 1234
 Database Scale http://slidesha.re/vC1i9x
 Sharding for startups http://bit.ly/vLa68N

21. Magento
Doctrine Common: Annotation reader
 Annotation is a class
 Any number of properties could be passed to
constructor
 Nesting
 Short forms
 Takes time to process

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Takes time to process?
All configuration is read from DI container
DI container is regenerated upon build
Dev. env. regenerates DI each request
Prod. env. reads cached DI
Annotations aren’t processed in prod. env.
PROFIT!

23. Magento
… well, mostly…
Not all is processed on build
Annotations are good for event
listeners *
Convenient way for storing meta-
information within the code
* Classes defined as services and tagged with special event hooks. Later
transformed to code in some of generated DIC methods.

24. Magento
Processing annotations
1. Create class implementing
SymfonyComponentDependencyInjectionCompiler
CompilerPassInterface
2. Collect annotations via reader
3. Save processed metadata in container via
ContainerBuilder::setParameter()
4. Add build(ContainerBuilder $cb) method to bundle
main class
5. Add kernel.* event observers
6. PROFIT

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Real life: collecting metadata

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Autowiring
 Inject serviced needed to places needed
 Reflection-heavy
 Hard, but possible for PHP
 MVC simplifying 
 Ready solutions
• Autowiring Bundle – http://bit.ly/uDTKYi
• JMSDiExtraBundle – http://bit.ly/t7pP89
• FLOW3 autowiring – http://bit.ly/tcJQ10

27. Magento
Common now is less: CRON
• Adding periodical tasks seem somewhat boring
• With annotated configuration it could be set up in
seconds
• This simple annotation will be transformed in
crontab file to something like
0 */4 * * * /usr/bin/php /path/to/app/console cli:call
our.user.service sendNotifications

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Doing things wrong?

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Doing things wrong
When my IDE* cannot help
auto completing I'm using
bad practice programming
* Netbeans, Eclipse, PHPStorm, .. put your favorite here

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Real life: Autowiring
 Create services with
simple annotating
them
 Inject existing services
to class properties
 Apply name guessing
strategies
 JMSDiExtraBundle
used

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Keeping code short
Configure routes
inline
Configure templates
inline
Inject only services,
that the action really
needs. Recognized by
IDE directly
Return needed variables for view

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grep
Nice tool to get only those classes
with annotations & autowiring to
parse
True UNIX way
Or use a class-map file – URL goes
here
Done at the build step

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Codegeneration and codedegeneration
 Programs program programs
 As ideal – lets developer develop business logic, not the
boilerplate
 Programs make pieces of programs
• RAD tools and frameworks
• IDE code templates
 Having templates is really good
 Customization is good
 “Code Generation in Action” by Jack Herrington D.
http://amzn.to/skQzEr

34. Magento
Use cases
Project rapid start
Enterprise stuff
DB interaction & ORM
Better unit test skeletons
Performance
Code transformation
Boilerplates & customization
Bunch of routine stuff …

35. Magento
Use-case: Generating unit-tests
Goal: save time creating boilerplate code
for
• Initialization of all dependent objects
• Public methods
• Possible conditional logic
• Asserting actual and expected results
• Mock object methods boilerplate

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How?
Wrapper over token_get_all()
Reflection API
ZendReflection &
ZendCodeGenerator

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Use-case: proxy generation for performance
 Template engines – compile own markup to PHP
 Symfony DI Component – generates service bootstrap
in PHP
 JMSSecurityBundle – puts security checking to
generated proxies
 SymfonyGeneratorBundle – makes writing boilerplate
CRUD code for controllers and entities faster and
easier.
 Put your own here.

38. Magento
Common things
Framework specific
Define placeholders
Extend and Proxy
Liscov substitution principle
Have templates, that are editable
Have an easy way to make own templates
Regenerate stuff on architecture change

39. Magento
Existing solutions
PHP ecosystem
 Symfony2 – SensioGeneratorBundle – http://symfony.com/
 Doctrine2 – two-way ORM/DB generator – http://bit.ly/veIvvm
 ZendFramework – ZendCodeGenerator – http://bit.ly/s7mYHD
 cg-library – http://bit.ly/vtBfk7
 QCodo – interesting RAD generator – http://qcodo.com/
 CakePHP – RAD project start - http://cakephp.org/
Other
 CodeSmith – http://codesmithtools.com/
…

40. Magento
Generating codegenerators
Have an ideal code sample: R&D
something nice 
Get code slice from line X to line Y
Define common pattern fast
Get template. Test it. Improve
sample.
Apply results of your concept fast

41. Magento
In 6 months …
Improve ideal code sample
Improve template
Regenerate those hundreds of files
in seconds with compatibility kept
PROFIT.

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A tool
 Some internal tool for generating generators, unit tests, fixtures
 Typical usage:
Sample file Start and end lines
Format
$ pugooroo tpl RolseService.php 108 118
Copy output
--pieces --heredoc --copy
Pick vars to buffer 
--function generateStuff
cogen> Enter code pieces you want to replace Wrap up to
function
user
Interactive
group
CLI app!11
Group
cogen> Enter alias for 'user' [piece0]: FIRST
cogen> Enter alias for 'group' [piece1]: SECOND
cogen> Enter alias for 'Group' [piece2]: SECOND_CAMELCASED

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And typical result
function generateStuff ($FIRST, $SECOND, $SECOND_CAMELCASED) {
$tmpl = <<<EOF
${$FIRST}Counts = array();
while ($row = $stmt->fetchObject()) {
${$FIRST}Counts[(int) $row->{$SECOND}_id] = (int) $row-
>num_{$FIRST}s;
}
foreach(${$SECOND}s as ${$SECOND}) {
/* @var ${$SECOND} {$SECOND_CAMELCASED} */
if(isset (${$FIRST}Counts[${$SECOND}->getId()])) {
${$SECOND}->setUsercount(${$FIRST}Counts[${$SECOND}->getId()]);
}
}
EOF;
return $tmpl;
}

44. Magento
CLI: interaction & copy to buffer
Interaction: streams
• php://stdin
• php://stdout
Copy to buffer from CLI:
• MacOS: echo $res | pbcopy
• Linux: echo $res | xclip …
• Windows: 

45. Magento
The more sophisticated things
#Joined array turns out to be more flexible than HEREDOC:
function generateStuff ($FIRST, $SECOND, $SECOND_CAMELCASED, $needsSomething =
true) {
$tmpl = array();
$tmpl[] = " ${$FIRST}Counts = array();";
$tmpl[] = " while ($row = $stmt->fetchObject()) {";
$tmpl[] = " ${$FIRST}Counts[(int) $row->{$SECOND}_id] = (int) $row-
>num_{$FIRST}s;";
$tmpl[] = " }";
$tmpl[] = " ";
if($needsSomething) {
$tmpl[] = " foreach(${$SECOND}s as ${$SECOND}) {";
$tmpl[] = " if(isset (${$FIRST}Counts[${$SECOND}-
>getId()])) {";
$tmpl[] = " ${$SECOND}-
>setUsercount(${$FIRST}Counts[${$SECOND}->getId()]);";
$tmpl[] = " }";
$tmpl[] = " }";
$tmpl[] = "";
}
$tmpl = join("n", $tmpl);
return $tmpl;
}

46. Magento
Real life: tagged keys in cache
Goal:
• Resultset of a method could be cached
• Resultset is dependent on other resultsets validity
• If dependent resultset becomes invalid – invalidate only
needed keys
• Perform application-wide substitutions like currently logged in
user and etc
• Make adding and removing cache really easy
Bad things
• Require complex code to maintain
• Hard to read

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Solution
 Java EhCache framework – http://ehcache.org/
 @Cacheable & @TriggersRemove with tagging-
specific features
 Generate code for proxy class
 Substitute original class within inversion of
control container
 Call the same method without any API change
 Turn off caching when needed

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Slight changes to code

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Generated code for caching

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Real life: add security restrictions
 Goal:
• Protect methods of service from unauthorized access
• Have access granularity to actions of controller
• Limit access for modifying particular entities
• Make it easy
 Solutions:
• Symfony2 – JmsSecurityExtraBundle – http://bit.ly/sX0hN6
• DiExtraBundle – autowiring stuff – http://bit.ly/t7pP89
• AopBundle – intercept method calls – http://bit.ly/vFqWSD

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Events

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Fast forms & XML
* Doctrine OXM: http://github.com/doctrine/oxm

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Questions &
Answers

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Thank you
• http://twitter.com/nf_x
• http://ua.linkedin.com/smertin